Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_bio.c
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1 /* 2 * Copyright (c) 1994,1997 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Absolutely no warranty of function or purpose is made by the author 12 * John S. Dyson. 13 * 14 * $FreeBSD$ 15 */ 16 17 /* 18 * this file contains a new buffer I/O scheme implementing a coherent 19 * VM object and buffer cache scheme. Pains have been taken to make 20 * sure that the performance degradation associated with schemes such 21 * as this is not realized. 22 * 23 * Author: John S. Dyson 24 * Significant help during the development and debugging phases 25 * had been provided by David Greenman, also of the FreeBSD core team. 26 * 27 * see man buf(9) for more info. 28 */ 29 30 #define VMIO 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/sysproto.h> 34 #include <sys/kernel.h> 35 #include <sys/sysctl.h> 36 #include <sys/proc.h> 37 #include <sys/vnode.h> 38 #include <sys/vmmeter.h> 39 #include <sys/lock.h> 40 #include <miscfs/specfs/specdev.h> 41 #include <vm/vm.h> 42 #include <vm/vm_param.h> 43 #include <vm/vm_prot.h> 44 #include <vm/vm_kern.h> 45 #include <vm/vm_pageout.h> 46 #include <vm/vm_page.h> 47 #include <vm/vm_object.h> 48 #include <vm/vm_extern.h> 49 #include <vm/vm_map.h> 50 #include <sys/buf.h> 51 #include <sys/mount.h> 52 #include <sys/malloc.h> 53 #include <sys/resourcevar.h> 54 55 static MALLOC_DEFINE(M_BIOBUF, "BIO buffer", "BIO buffer"); 56 57 struct bio_ops bioops; /* I/O operation notification */ 58 59 #if 0 /* replaced bu sched_sync */ 60 static void vfs_update __P((void)); 61 static struct proc *updateproc; 62 static struct kproc_desc up_kp = { 63 "update", 64 vfs_update, 65 &updateproc 66 }; 67 SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp) 68 #endif 69 70 struct buf *buf; /* buffer header pool */ 71 struct swqueue bswlist; 72 73 static void vm_hold_free_pages(struct buf * bp, vm_offset_t from, 74 vm_offset_t to); 75 static void vm_hold_load_pages(struct buf * bp, vm_offset_t from, 76 vm_offset_t to); 77 static void vfs_buf_set_valid(struct buf *bp, vm_ooffset_t foff, 78 vm_offset_t off, vm_offset_t size, 79 vm_page_t m); 80 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, 81 int pageno, vm_page_t m); 82 static void vfs_clean_pages(struct buf * bp); 83 static void vfs_setdirty(struct buf *bp); 84 static void vfs_vmio_release(struct buf *bp); 85 static void flushdirtybuffers(int slpflag, int slptimeo); 86 87 int needsbuffer; 88 89 /* 90 * Internal update daemon, process 3 91 * The variable vfs_update_wakeup allows for internal syncs. 92 */ 93 int vfs_update_wakeup; 94 95 96 /* 97 * buffers base kva 98 */ 99 100 /* 101 * bogus page -- for I/O to/from partially complete buffers 102 * this is a temporary solution to the problem, but it is not 103 * really that bad. it would be better to split the buffer 104 * for input in the case of buffers partially already in memory, 105 * but the code is intricate enough already. 106 */ 107 vm_page_t bogus_page; 108 static vm_offset_t bogus_offset; 109 110 static int bufspace, maxbufspace, vmiospace, maxvmiobufspace, 111 bufmallocspace, maxbufmallocspace; 112 int numdirtybuffers; 113 static int lodirtybuffers, hidirtybuffers; 114 static int numfreebuffers, lofreebuffers, hifreebuffers; 115 static int kvafreespace; 116 117 SYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, 118 &numdirtybuffers, 0, ""); 119 SYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, 120 &lodirtybuffers, 0, ""); 121 SYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, 122 &hidirtybuffers, 0, ""); 123 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, 124 &numfreebuffers, 0, ""); 125 SYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, 126 &lofreebuffers, 0, ""); 127 SYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, 128 &hifreebuffers, 0, ""); 129 SYSCTL_INT(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RW, 130 &maxbufspace, 0, ""); 131 SYSCTL_INT(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, 132 &bufspace, 0, ""); 133 SYSCTL_INT(_vfs, OID_AUTO, maxvmiobufspace, CTLFLAG_RW, 134 &maxvmiobufspace, 0, ""); 135 SYSCTL_INT(_vfs, OID_AUTO, vmiospace, CTLFLAG_RD, 136 &vmiospace, 0, ""); 137 SYSCTL_INT(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, 138 &maxbufmallocspace, 0, ""); 139 SYSCTL_INT(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, 140 &bufmallocspace, 0, ""); 141 SYSCTL_INT(_vfs, OID_AUTO, kvafreespace, CTLFLAG_RD, 142 &kvafreespace, 0, ""); 143 144 static LIST_HEAD(bufhashhdr, buf) bufhashtbl[BUFHSZ], invalhash; 145 struct bqueues bufqueues[BUFFER_QUEUES] = {0}; 146 147 extern int vm_swap_size; 148 149 #define BUF_MAXUSE 24 150 151 #define VFS_BIO_NEED_ANY 1 152 #define VFS_BIO_NEED_LOWLIMIT 2 153 #define VFS_BIO_NEED_FREE 4 154 155 /* 156 * Initialize buffer headers and related structures. 157 */ 158 void 159 bufinit() 160 { 161 struct buf *bp; 162 int i; 163 164 TAILQ_INIT(&bswlist); 165 LIST_INIT(&invalhash); 166 167 /* first, make a null hash table */ 168 for (i = 0; i < BUFHSZ; i++) 169 LIST_INIT(&bufhashtbl[i]); 170 171 /* next, make a null set of free lists */ 172 for (i = 0; i < BUFFER_QUEUES; i++) 173 TAILQ_INIT(&bufqueues[i]); 174 175 /* finally, initialize each buffer header and stick on empty q */ 176 for (i = 0; i < nbuf; i++) { 177 bp = &buf[i]; 178 bzero(bp, sizeof *bp); 179 bp->b_flags = B_INVAL; /* we're just an empty header */ 180 bp->b_dev = NODEV; 181 bp->b_rcred = NOCRED; 182 bp->b_wcred = NOCRED; 183 bp->b_qindex = QUEUE_EMPTY; 184 bp->b_xflags = 0; 185 LIST_INIT(&bp->b_dep); 186 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 187 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 188 } 189 /* 190 * maxbufspace is currently calculated to support all filesystem blocks 191 * to be 8K. If you happen to use a 16K filesystem, the size of the buffer 192 * cache is still the same as it would be for 8K filesystems. This 193 * keeps the size of the buffer cache "in check" for big block filesystems. 194 */ 195 maxbufspace = (nbuf + 8) * DFLTBSIZE; 196 /* 197 * reserve 1/3 of the buffers for metadata (VDIR) which might not be VMIO'ed 198 */ 199 maxvmiobufspace = 2 * maxbufspace / 3; 200 /* 201 * Limit the amount of malloc memory since it is wired permanently into 202 * the kernel space. Even though this is accounted for in the buffer 203 * allocation, we don't want the malloced region to grow uncontrolled. 204 * The malloc scheme improves memory utilization significantly on average 205 * (small) directories. 206 */ 207 maxbufmallocspace = maxbufspace / 20; 208 209 /* 210 * Remove the probability of deadlock conditions by limiting the 211 * number of dirty buffers. 212 */ 213 hidirtybuffers = nbuf / 8 + 20; 214 lodirtybuffers = nbuf / 16 + 10; 215 numdirtybuffers = 0; 216 lofreebuffers = nbuf / 18 + 5; 217 hifreebuffers = 2 * lofreebuffers; 218 numfreebuffers = nbuf; 219 kvafreespace = 0; 220 221 bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE); 222 bogus_page = vm_page_alloc(kernel_object, 223 ((bogus_offset - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), 224 VM_ALLOC_NORMAL); 225 226 } 227 228 /* 229 * Free the kva allocation for a buffer 230 * Must be called only at splbio or higher, 231 * as this is the only locking for buffer_map. 232 */ 233 static void 234 bfreekva(struct buf * bp) 235 { 236 if (bp->b_kvasize == 0) 237 return; 238 239 vm_map_delete(buffer_map, 240 (vm_offset_t) bp->b_kvabase, 241 (vm_offset_t) bp->b_kvabase + bp->b_kvasize); 242 243 bp->b_kvasize = 0; 244 245 } 246 247 /* 248 * remove the buffer from the appropriate free list 249 */ 250 void 251 bremfree(struct buf * bp) 252 { 253 int s = splbio(); 254 255 if (bp->b_qindex != QUEUE_NONE) { 256 if (bp->b_qindex == QUEUE_EMPTY) { 257 kvafreespace -= bp->b_kvasize; 258 } 259 TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); 260 bp->b_qindex = QUEUE_NONE; 261 } else { 262 #if !defined(MAX_PERF) 263 panic("bremfree: removing a buffer when not on a queue"); 264 #endif 265 } 266 if ((bp->b_flags & B_INVAL) || 267 (bp->b_flags & (B_DELWRI|B_LOCKED)) == 0) 268 --numfreebuffers; 269 splx(s); 270 } 271 272 273 /* 274 * Get a buffer with the specified data. Look in the cache first. 275 */ 276 int 277 bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred, 278 struct buf ** bpp) 279 { 280 struct buf *bp; 281 282 bp = getblk(vp, blkno, size, 0, 0); 283 *bpp = bp; 284 285 /* if not found in cache, do some I/O */ 286 if ((bp->b_flags & B_CACHE) == 0) { 287 if (curproc != NULL) 288 curproc->p_stats->p_ru.ru_inblock++; 289 bp->b_flags |= B_READ; 290 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 291 if (bp->b_rcred == NOCRED) { 292 if (cred != NOCRED) 293 crhold(cred); 294 bp->b_rcred = cred; 295 } 296 vfs_busy_pages(bp, 0); 297 VOP_STRATEGY(vp, bp); 298 return (biowait(bp)); 299 } 300 return (0); 301 } 302 303 /* 304 * Operates like bread, but also starts asynchronous I/O on 305 * read-ahead blocks. 306 */ 307 int 308 breadn(struct vnode * vp, daddr_t blkno, int size, 309 daddr_t * rablkno, int *rabsize, 310 int cnt, struct ucred * cred, struct buf ** bpp) 311 { 312 struct buf *bp, *rabp; 313 int i; 314 int rv = 0, readwait = 0; 315 316 *bpp = bp = getblk(vp, blkno, size, 0, 0); 317 318 /* if not found in cache, do some I/O */ 319 if ((bp->b_flags & B_CACHE) == 0) { 320 if (curproc != NULL) 321 curproc->p_stats->p_ru.ru_inblock++; 322 bp->b_flags |= B_READ; 323 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 324 if (bp->b_rcred == NOCRED) { 325 if (cred != NOCRED) 326 crhold(cred); 327 bp->b_rcred = cred; 328 } 329 vfs_busy_pages(bp, 0); 330 VOP_STRATEGY(vp, bp); 331 ++readwait; 332 } 333 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 334 if (inmem(vp, *rablkno)) 335 continue; 336 rabp = getblk(vp, *rablkno, *rabsize, 0, 0); 337 338 if ((rabp->b_flags & B_CACHE) == 0) { 339 if (curproc != NULL) 340 curproc->p_stats->p_ru.ru_inblock++; 341 rabp->b_flags |= B_READ | B_ASYNC; 342 rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 343 if (rabp->b_rcred == NOCRED) { 344 if (cred != NOCRED) 345 crhold(cred); 346 rabp->b_rcred = cred; 347 } 348 vfs_busy_pages(rabp, 0); 349 VOP_STRATEGY(vp, rabp); 350 } else { 351 brelse(rabp); 352 } 353 } 354 355 if (readwait) { 356 rv = biowait(bp); 357 } 358 return (rv); 359 } 360 361 /* 362 * Write, release buffer on completion. (Done by iodone 363 * if async.) 364 */ 365 int 366 bwrite(struct buf * bp) 367 { 368 int oldflags, s; 369 struct vnode *vp; 370 struct mount *mp; 371 372 373 if (bp->b_flags & B_INVAL) { 374 brelse(bp); 375 return (0); 376 } 377 378 oldflags = bp->b_flags; 379 380 #if !defined(MAX_PERF) 381 if ((bp->b_flags & B_BUSY) == 0) 382 panic("bwrite: buffer is not busy???"); 383 #endif 384 385 bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI); 386 bp->b_flags |= B_WRITEINPROG; 387 388 s = splbio(); 389 if ((oldflags & B_DELWRI) == B_DELWRI) { 390 --numdirtybuffers; 391 reassignbuf(bp, bp->b_vp); 392 } 393 394 bp->b_vp->v_numoutput++; 395 vfs_busy_pages(bp, 1); 396 if (curproc != NULL) 397 curproc->p_stats->p_ru.ru_oublock++; 398 splx(s); 399 VOP_STRATEGY(bp->b_vp, bp); 400 401 /* 402 * Collect statistics on synchronous and asynchronous writes. 403 * Writes to block devices are charged to their associated 404 * filesystem (if any). 405 */ 406 if ((vp = bp->b_vp) != NULL) { 407 if (vp->v_type == VBLK) 408 mp = vp->v_specmountpoint; 409 else 410 mp = vp->v_mount; 411 if (mp != NULL) 412 if ((oldflags & B_ASYNC) == 0) 413 mp->mnt_stat.f_syncwrites++; 414 else 415 mp->mnt_stat.f_asyncwrites++; 416 } 417 418 if ((oldflags & B_ASYNC) == 0) { 419 int rtval = biowait(bp); 420 brelse(bp); 421 return (rtval); 422 } 423 return (0); 424 } 425 426 void 427 vfs_bio_need_satisfy(void) { 428 ++numfreebuffers; 429 if (!needsbuffer) 430 return; 431 if (numdirtybuffers < lodirtybuffers) { 432 needsbuffer &= ~(VFS_BIO_NEED_ANY | VFS_BIO_NEED_LOWLIMIT); 433 } else { 434 needsbuffer &= ~VFS_BIO_NEED_ANY; 435 } 436 if (numfreebuffers >= hifreebuffers) { 437 needsbuffer &= ~VFS_BIO_NEED_FREE; 438 } 439 wakeup(&needsbuffer); 440 } 441 442 /* 443 * Delayed write. (Buffer is marked dirty). 444 */ 445 void 446 bdwrite(struct buf * bp) 447 { 448 struct vnode *vp; 449 450 #if !defined(MAX_PERF) 451 if ((bp->b_flags & B_BUSY) == 0) { 452 panic("bdwrite: buffer is not busy"); 453 } 454 #endif 455 456 if (bp->b_flags & B_INVAL) { 457 brelse(bp); 458 return; 459 } 460 bp->b_flags &= ~(B_READ|B_RELBUF); 461 if ((bp->b_flags & B_DELWRI) == 0) { 462 bp->b_flags |= B_DONE | B_DELWRI; 463 reassignbuf(bp, bp->b_vp); 464 ++numdirtybuffers; 465 } 466 467 /* 468 * This bmap keeps the system from needing to do the bmap later, 469 * perhaps when the system is attempting to do a sync. Since it 470 * is likely that the indirect block -- or whatever other datastructure 471 * that the filesystem needs is still in memory now, it is a good 472 * thing to do this. Note also, that if the pageout daemon is 473 * requesting a sync -- there might not be enough memory to do 474 * the bmap then... So, this is important to do. 475 */ 476 if (bp->b_lblkno == bp->b_blkno) { 477 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 478 } 479 480 /* 481 * Set the *dirty* buffer range based upon the VM system dirty pages. 482 */ 483 vfs_setdirty(bp); 484 485 /* 486 * We need to do this here to satisfy the vnode_pager and the 487 * pageout daemon, so that it thinks that the pages have been 488 * "cleaned". Note that since the pages are in a delayed write 489 * buffer -- the VFS layer "will" see that the pages get written 490 * out on the next sync, or perhaps the cluster will be completed. 491 */ 492 vfs_clean_pages(bp); 493 bqrelse(bp); 494 495 /* 496 * XXX The soft dependency code is not prepared to 497 * have I/O done when a bdwrite is requested. For 498 * now we just let the write be delayed if it is 499 * requested by the soft dependency code. 500 */ 501 if ((vp = bp->b_vp) && 502 ((vp->v_type == VBLK && vp->v_specmountpoint && 503 (vp->v_specmountpoint->mnt_flag & MNT_SOFTDEP)) || 504 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP)))) 505 return; 506 507 if (numdirtybuffers >= hidirtybuffers) 508 flushdirtybuffers(0, 0); 509 510 return; 511 } 512 513 514 /* 515 * Same as first half of bdwrite, mark buffer dirty, but do not release it. 516 * Check how this compares with vfs_setdirty(); XXX [JRE] 517 */ 518 void 519 bdirty(bp) 520 struct buf *bp; 521 { 522 523 bp->b_flags &= ~(B_READ|B_RELBUF); /* XXX ??? check this */ 524 if ((bp->b_flags & B_DELWRI) == 0) { 525 bp->b_flags |= B_DONE | B_DELWRI; /* why done? XXX JRE */ 526 reassignbuf(bp, bp->b_vp); 527 ++numdirtybuffers; 528 } 529 } 530 531 /* 532 * Asynchronous write. 533 * Start output on a buffer, but do not wait for it to complete. 534 * The buffer is released when the output completes. 535 */ 536 void 537 bawrite(struct buf * bp) 538 { 539 bp->b_flags |= B_ASYNC; 540 (void) VOP_BWRITE(bp); 541 } 542 543 /* 544 * Ordered write. 545 * Start output on a buffer, and flag it so that the device will write 546 * it in the order it was queued. The buffer is released when the output 547 * completes. 548 */ 549 int 550 bowrite(struct buf * bp) 551 { 552 bp->b_flags |= B_ORDERED|B_ASYNC; 553 return (VOP_BWRITE(bp)); 554 } 555 556 /* 557 * Release a buffer. 558 */ 559 void 560 brelse(struct buf * bp) 561 { 562 int s; 563 564 if (bp->b_flags & B_CLUSTER) { 565 relpbuf(bp); 566 return; 567 } 568 569 s = splbio(); 570 571 /* anyone need this block? */ 572 if (bp->b_flags & B_WANTED) { 573 bp->b_flags &= ~(B_WANTED | B_AGE); 574 wakeup(bp); 575 } 576 577 if (bp->b_flags & B_LOCKED) 578 bp->b_flags &= ~B_ERROR; 579 580 if ((bp->b_flags & (B_READ | B_ERROR)) == B_ERROR) { 581 bp->b_flags &= ~B_ERROR; 582 bdirty(bp); 583 } else if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_FREEBUF)) || 584 (bp->b_bufsize <= 0)) { 585 bp->b_flags |= B_INVAL; 586 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_deallocate) 587 (*bioops.io_deallocate)(bp); 588 if (bp->b_flags & B_DELWRI) 589 --numdirtybuffers; 590 bp->b_flags &= ~(B_DELWRI | B_CACHE | B_FREEBUF); 591 if ((bp->b_flags & B_VMIO) == 0) { 592 if (bp->b_bufsize) 593 allocbuf(bp, 0); 594 if (bp->b_vp) 595 brelvp(bp); 596 } 597 } 598 599 /* 600 * We must clear B_RELBUF if B_DELWRI is set. If vfs_vmio_release() 601 * is called with B_DELWRI set, the underlying pages may wind up 602 * getting freed causing a previous write (bdwrite()) to get 'lost' 603 * because pages associated with a B_DELWRI bp are marked clean. 604 * 605 * We still allow the B_INVAL case to call vfs_vmio_release(), even 606 * if B_DELWRI is set. 607 */ 608 609 if (bp->b_flags & B_DELWRI) 610 bp->b_flags &= ~B_RELBUF; 611 612 /* 613 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 614 * constituted, so the B_INVAL flag is used to *invalidate* the buffer, 615 * but the VM object is kept around. The B_NOCACHE flag is used to 616 * invalidate the pages in the VM object. 617 * 618 * The b_{validoff,validend,dirtyoff,dirtyend} values are relative 619 * to b_offset and currently have byte granularity, whereas the 620 * valid flags in the vm_pages have only DEV_BSIZE resolution. 621 * The byte resolution fields are used to avoid unnecessary re-reads 622 * of the buffer but the code really needs to be genericized so 623 * other filesystem modules can take advantage of these fields. 624 * 625 * XXX this seems to cause performance problems. 626 */ 627 if ((bp->b_flags & B_VMIO) 628 && !(bp->b_vp->v_tag == VT_NFS && 629 bp->b_vp->v_type != VBLK && 630 (bp->b_flags & B_DELWRI) != 0) 631 #ifdef notdef 632 && (bp->b_vp->v_tag != VT_NFS 633 || bp->b_vp->v_type == VBLK 634 || (bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) 635 || bp->b_validend == 0 636 || (bp->b_validoff == 0 637 && bp->b_validend == bp->b_bufsize)) 638 #endif 639 ) { 640 641 int i, j, resid; 642 vm_page_t m; 643 off_t foff; 644 vm_pindex_t poff; 645 vm_object_t obj; 646 struct vnode *vp; 647 648 vp = bp->b_vp; 649 650 /* 651 * Get the base offset and length of the buffer. Note that 652 * for block sizes that are less then PAGE_SIZE, the b_data 653 * base of the buffer does not represent exactly b_offset and 654 * neither b_offset nor b_size are necessarily page aligned. 655 * Instead, the starting position of b_offset is: 656 * 657 * b_data + (b_offset & PAGE_MASK) 658 * 659 * block sizes less then DEV_BSIZE (usually 512) are not 660 * supported due to the page granularity bits (m->valid, 661 * m->dirty, etc...). 662 * 663 * See man buf(9) for more information 664 */ 665 666 resid = bp->b_bufsize; 667 foff = bp->b_offset; 668 669 for (i = 0; i < bp->b_npages; i++) { 670 m = bp->b_pages[i]; 671 vm_page_flag_clear(m, PG_ZERO); 672 if (m == bogus_page) { 673 674 obj = (vm_object_t) vp->v_object; 675 poff = OFF_TO_IDX(bp->b_offset); 676 677 for (j = i; j < bp->b_npages; j++) { 678 m = bp->b_pages[j]; 679 if (m == bogus_page) { 680 m = vm_page_lookup(obj, poff + j); 681 #if !defined(MAX_PERF) 682 if (!m) { 683 panic("brelse: page missing\n"); 684 } 685 #endif 686 bp->b_pages[j] = m; 687 } 688 } 689 690 if ((bp->b_flags & B_INVAL) == 0) { 691 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), bp->b_pages, bp->b_npages); 692 } 693 } 694 if (bp->b_flags & (B_NOCACHE|B_ERROR)) { 695 int poffset = foff & PAGE_MASK; 696 int presid = resid > (PAGE_SIZE - poffset) ? 697 (PAGE_SIZE - poffset) : resid; 698 699 KASSERT(presid >= 0, ("brelse: extra page")); 700 vm_page_set_invalid(m, poffset, presid); 701 } 702 resid -= PAGE_SIZE - (foff & PAGE_MASK); 703 foff = (foff + PAGE_SIZE) & ~PAGE_MASK; 704 } 705 706 if (bp->b_flags & (B_INVAL | B_RELBUF)) 707 vfs_vmio_release(bp); 708 709 } else if (bp->b_flags & B_VMIO) { 710 711 if (bp->b_flags & (B_INVAL | B_RELBUF)) 712 vfs_vmio_release(bp); 713 714 } 715 716 #if !defined(MAX_PERF) 717 if (bp->b_qindex != QUEUE_NONE) 718 panic("brelse: free buffer onto another queue???"); 719 #endif 720 721 /* enqueue */ 722 /* buffers with no memory */ 723 if (bp->b_bufsize == 0) { 724 bp->b_flags |= B_INVAL; 725 bp->b_qindex = QUEUE_EMPTY; 726 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 727 LIST_REMOVE(bp, b_hash); 728 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 729 bp->b_dev = NODEV; 730 kvafreespace += bp->b_kvasize; 731 732 /* buffers with junk contents */ 733 } else if (bp->b_flags & (B_ERROR | B_INVAL | B_NOCACHE | B_RELBUF)) { 734 bp->b_flags |= B_INVAL; 735 bp->b_qindex = QUEUE_AGE; 736 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist); 737 LIST_REMOVE(bp, b_hash); 738 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 739 bp->b_dev = NODEV; 740 741 /* buffers that are locked */ 742 } else if (bp->b_flags & B_LOCKED) { 743 bp->b_qindex = QUEUE_LOCKED; 744 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); 745 746 /* buffers with stale but valid contents */ 747 } else if (bp->b_flags & B_AGE) { 748 bp->b_qindex = QUEUE_AGE; 749 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist); 750 751 /* buffers with valid and quite potentially reuseable contents */ 752 } else { 753 bp->b_qindex = QUEUE_LRU; 754 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 755 } 756 757 if ((bp->b_flags & B_INVAL) || 758 (bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { 759 if (bp->b_flags & B_DELWRI) { 760 --numdirtybuffers; 761 bp->b_flags &= ~B_DELWRI; 762 } 763 vfs_bio_need_satisfy(); 764 } 765 766 /* unlock */ 767 bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | 768 B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 769 splx(s); 770 } 771 772 /* 773 * Release a buffer. 774 */ 775 void 776 bqrelse(struct buf * bp) 777 { 778 int s; 779 780 s = splbio(); 781 782 /* anyone need this block? */ 783 if (bp->b_flags & B_WANTED) { 784 bp->b_flags &= ~(B_WANTED | B_AGE); 785 wakeup(bp); 786 } 787 788 #if !defined(MAX_PERF) 789 if (bp->b_qindex != QUEUE_NONE) 790 panic("bqrelse: free buffer onto another queue???"); 791 #endif 792 793 if (bp->b_flags & B_LOCKED) { 794 bp->b_flags &= ~B_ERROR; 795 bp->b_qindex = QUEUE_LOCKED; 796 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); 797 /* buffers with stale but valid contents */ 798 } else { 799 bp->b_qindex = QUEUE_LRU; 800 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 801 } 802 803 if ((bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { 804 vfs_bio_need_satisfy(); 805 } 806 807 /* unlock */ 808 bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | 809 B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 810 splx(s); 811 } 812 813 static void 814 vfs_vmio_release(bp) 815 struct buf *bp; 816 { 817 int i, s; 818 vm_page_t m; 819 820 s = splvm(); 821 for (i = 0; i < bp->b_npages; i++) { 822 m = bp->b_pages[i]; 823 bp->b_pages[i] = NULL; 824 /* 825 * In order to keep page LRU ordering consistent, put 826 * everything on the inactive queue. 827 */ 828 vm_page_unwire(m, 0); 829 /* 830 * We don't mess with busy pages, it is 831 * the responsibility of the process that 832 * busied the pages to deal with them. 833 */ 834 if ((m->flags & PG_BUSY) || (m->busy != 0)) 835 continue; 836 837 if (m->wire_count == 0) { 838 vm_page_flag_clear(m, PG_ZERO); 839 /* 840 * Might as well free the page if we can and it has 841 * no valid data. 842 */ 843 if ((bp->b_flags & B_ASYNC) == 0 && !m->valid && m->hold_count == 0) { 844 vm_page_busy(m); 845 vm_page_protect(m, VM_PROT_NONE); 846 vm_page_free(m); 847 } 848 } 849 } 850 splx(s); 851 bufspace -= bp->b_bufsize; 852 vmiospace -= bp->b_bufsize; 853 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 854 bp->b_npages = 0; 855 bp->b_bufsize = 0; 856 bp->b_flags &= ~B_VMIO; 857 if (bp->b_vp) 858 brelvp(bp); 859 } 860 861 /* 862 * Check to see if a block is currently memory resident. 863 */ 864 struct buf * 865 gbincore(struct vnode * vp, daddr_t blkno) 866 { 867 struct buf *bp; 868 struct bufhashhdr *bh; 869 870 bh = BUFHASH(vp, blkno); 871 bp = bh->lh_first; 872 873 /* Search hash chain */ 874 while (bp != NULL) { 875 /* hit */ 876 if (bp->b_vp == vp && bp->b_lblkno == blkno && 877 (bp->b_flags & B_INVAL) == 0) { 878 break; 879 } 880 bp = bp->b_hash.le_next; 881 } 882 return (bp); 883 } 884 885 /* 886 * this routine implements clustered async writes for 887 * clearing out B_DELWRI buffers... This is much better 888 * than the old way of writing only one buffer at a time. 889 */ 890 int 891 vfs_bio_awrite(struct buf * bp) 892 { 893 int i; 894 daddr_t lblkno = bp->b_lblkno; 895 struct vnode *vp = bp->b_vp; 896 int s; 897 int ncl; 898 struct buf *bpa; 899 int nwritten; 900 int size; 901 int maxcl; 902 903 s = splbio(); 904 /* 905 * right now we support clustered writing only to regular files 906 */ 907 if ((vp->v_type == VREG) && 908 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 909 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 910 911 size = vp->v_mount->mnt_stat.f_iosize; 912 maxcl = MAXPHYS / size; 913 914 for (i = 1; i < maxcl; i++) { 915 if ((bpa = gbincore(vp, lblkno + i)) && 916 ((bpa->b_flags & (B_BUSY | B_DELWRI | B_CLUSTEROK | B_INVAL)) == 917 (B_DELWRI | B_CLUSTEROK)) && 918 (bpa->b_bufsize == size)) { 919 if ((bpa->b_blkno == bpa->b_lblkno) || 920 (bpa->b_blkno != bp->b_blkno + ((i * size) >> DEV_BSHIFT))) 921 break; 922 } else { 923 break; 924 } 925 } 926 ncl = i; 927 /* 928 * this is a possible cluster write 929 */ 930 if (ncl != 1) { 931 nwritten = cluster_wbuild(vp, size, lblkno, ncl); 932 splx(s); 933 return nwritten; 934 } 935 } 936 937 bremfree(bp); 938 bp->b_flags |= B_BUSY | B_ASYNC; 939 940 splx(s); 941 /* 942 * default (old) behavior, writing out only one block 943 */ 944 nwritten = bp->b_bufsize; 945 (void) VOP_BWRITE(bp); 946 return nwritten; 947 } 948 949 950 /* 951 * Find a buffer header which is available for use. 952 */ 953 static struct buf * 954 getnewbuf(struct vnode *vp, daddr_t blkno, 955 int slpflag, int slptimeo, int size, int maxsize) 956 { 957 struct buf *bp, *bp1; 958 int nbyteswritten = 0; 959 vm_offset_t addr; 960 static int writerecursion = 0; 961 962 start: 963 if (bufspace >= maxbufspace) 964 goto trytofreespace; 965 966 /* can we constitute a new buffer? */ 967 if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]))) { 968 #if !defined(MAX_PERF) 969 if (bp->b_qindex != QUEUE_EMPTY) 970 panic("getnewbuf: inconsistent EMPTY queue, qindex=%d", 971 bp->b_qindex); 972 #endif 973 bp->b_flags |= B_BUSY; 974 bremfree(bp); 975 goto fillbuf; 976 } 977 trytofreespace: 978 /* 979 * We keep the file I/O from hogging metadata I/O 980 * This is desirable because file data is cached in the 981 * VM/Buffer cache even if a buffer is freed. 982 */ 983 if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]))) { 984 #if !defined(MAX_PERF) 985 if (bp->b_qindex != QUEUE_AGE) 986 panic("getnewbuf: inconsistent AGE queue, qindex=%d", 987 bp->b_qindex); 988 #endif 989 } else if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]))) { 990 #if !defined(MAX_PERF) 991 if (bp->b_qindex != QUEUE_LRU) 992 panic("getnewbuf: inconsistent LRU queue, qindex=%d", 993 bp->b_qindex); 994 #endif 995 } 996 if (!bp) { 997 /* wait for a free buffer of any kind */ 998 needsbuffer |= VFS_BIO_NEED_ANY; 999 do 1000 if (tsleep(&needsbuffer, (PRIBIO + 4) | slpflag, 1001 "newbuf", slptimeo)) 1002 return (NULL); 1003 while (needsbuffer & VFS_BIO_NEED_ANY); 1004 return (0); 1005 } 1006 KASSERT(!(bp->b_flags & B_BUSY), 1007 ("getnewbuf: busy buffer on free list\n")); 1008 /* 1009 * We are fairly aggressive about freeing VMIO buffers, but since 1010 * the buffering is intact without buffer headers, there is not 1011 * much loss. We gain by maintaining non-VMIOed metadata in buffers. 1012 */ 1013 if ((bp->b_qindex == QUEUE_LRU) && (bp->b_usecount > 0)) { 1014 if ((bp->b_flags & B_VMIO) == 0 || 1015 (vmiospace < maxvmiobufspace)) { 1016 --bp->b_usecount; 1017 TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist); 1018 if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) { 1019 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1020 goto start; 1021 } 1022 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1023 } 1024 } 1025 1026 1027 /* if we are a delayed write, convert to an async write */ 1028 if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) { 1029 1030 /* 1031 * If our delayed write is likely to be used soon, then 1032 * recycle back onto the LRU queue. 1033 */ 1034 if (vp && (bp->b_vp == vp) && (bp->b_qindex == QUEUE_LRU) && 1035 (bp->b_lblkno >= blkno) && (maxsize > 0)) { 1036 1037 if (bp->b_usecount > 0) { 1038 if (bp->b_lblkno < blkno + (MAXPHYS / maxsize)) { 1039 1040 TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist); 1041 1042 if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) { 1043 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1044 bp->b_usecount--; 1045 goto start; 1046 } 1047 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1048 } 1049 } 1050 } 1051 1052 /* 1053 * Certain layered filesystems can recursively re-enter the vfs_bio 1054 * code, due to delayed writes. This helps keep the system from 1055 * deadlocking. 1056 * This hack to avoid premature panic is courtesy of alfred 1057 * (alfred@freebsd.org) 1058 */ 1059 if (writerecursion > 0) { 1060 if (writerecursion > 5) { 1061 int loop = 0; 1062 norecurse: 1063 bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); 1064 while (bp) { 1065 if ((bp->b_flags & B_DELWRI) == 0) 1066 break; 1067 bp = TAILQ_NEXT(bp, b_freelist); 1068 } 1069 if (bp == NULL) { 1070 bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); 1071 while (bp) { 1072 if ((bp->b_flags & B_DELWRI) == 0) 1073 break; 1074 bp = TAILQ_NEXT(bp, b_freelist); 1075 } 1076 } 1077 if (bp == NULL) { 1078 needsbuffer |= VFS_BIO_NEED_ANY; 1079 if (tsleep(&needsbuffer, 1080 (PRIBIO + 4) | slpflag, 1081 "nbufhack", slptimeo+1)) 1082 return (NULL); 1083 if (loop++ < 5) 1084 goto norecurse; 1085 else 1086 goto start; 1087 } 1088 } else { 1089 bremfree(bp); 1090 bp->b_flags |= B_BUSY | B_AGE | B_ASYNC; 1091 nbyteswritten += bp->b_bufsize; 1092 ++writerecursion; 1093 VOP_BWRITE(bp); 1094 --writerecursion; 1095 if (!slpflag && !slptimeo) { 1096 return (0); 1097 } 1098 goto start; 1099 } 1100 } else { 1101 ++writerecursion; 1102 nbyteswritten += vfs_bio_awrite(bp); 1103 --writerecursion; 1104 if (!slpflag && !slptimeo) { 1105 return (0); 1106 } 1107 goto start; 1108 } 1109 } 1110 1111 if (bp->b_flags & B_WANTED) { 1112 bp->b_flags &= ~B_WANTED; 1113 wakeup(bp); 1114 } 1115 bremfree(bp); 1116 bp->b_flags |= B_BUSY; 1117 1118 if (bp->b_flags & B_VMIO) { 1119 bp->b_flags &= ~B_ASYNC; 1120 vfs_vmio_release(bp); 1121 } 1122 1123 if (bp->b_vp) 1124 brelvp(bp); 1125 1126 fillbuf: 1127 1128 /* we are not free, nor do we contain interesting data */ 1129 if (bp->b_rcred != NOCRED) { 1130 crfree(bp->b_rcred); 1131 bp->b_rcred = NOCRED; 1132 } 1133 if (bp->b_wcred != NOCRED) { 1134 crfree(bp->b_wcred); 1135 bp->b_wcred = NOCRED; 1136 } 1137 if (LIST_FIRST(&bp->b_dep) != NULL && 1138 bioops.io_deallocate) 1139 (*bioops.io_deallocate)(bp); 1140 1141 LIST_REMOVE(bp, b_hash); 1142 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 1143 if (bp->b_bufsize) { 1144 allocbuf(bp, 0); 1145 } 1146 bp->b_flags = B_BUSY; 1147 bp->b_dev = NODEV; 1148 bp->b_vp = NULL; 1149 bp->b_blkno = bp->b_lblkno = 0; 1150 bp->b_offset = NOOFFSET; 1151 bp->b_iodone = 0; 1152 bp->b_error = 0; 1153 bp->b_resid = 0; 1154 bp->b_bcount = 0; 1155 bp->b_npages = 0; 1156 bp->b_dirtyoff = bp->b_dirtyend = 0; 1157 bp->b_validoff = bp->b_validend = 0; 1158 bp->b_usecount = 5; 1159 /* Here, not kern_physio.c, is where this should be done*/ 1160 LIST_INIT(&bp->b_dep); 1161 1162 maxsize = (maxsize + PAGE_MASK) & ~PAGE_MASK; 1163 1164 /* 1165 * we assume that buffer_map is not at address 0 1166 */ 1167 addr = 0; 1168 if (maxsize != bp->b_kvasize) { 1169 bfreekva(bp); 1170 1171 findkvaspace: 1172 /* 1173 * See if we have buffer kva space 1174 */ 1175 if (vm_map_findspace(buffer_map, 1176 vm_map_min(buffer_map), maxsize, &addr)) { 1177 if (kvafreespace > 0) { 1178 int totfree = 0, freed; 1179 do { 1180 freed = 0; 1181 for (bp1 = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]); 1182 bp1 != NULL; bp1 = TAILQ_NEXT(bp1, b_freelist)) { 1183 if (bp1->b_kvasize != 0) { 1184 totfree += bp1->b_kvasize; 1185 freed = bp1->b_kvasize; 1186 bremfree(bp1); 1187 bfreekva(bp1); 1188 brelse(bp1); 1189 break; 1190 } 1191 } 1192 } while (freed); 1193 /* 1194 * if we found free space, then retry with the same buffer. 1195 */ 1196 if (totfree) 1197 goto findkvaspace; 1198 } 1199 bp->b_flags |= B_INVAL; 1200 brelse(bp); 1201 goto trytofreespace; 1202 } 1203 } 1204 1205 /* 1206 * See if we are below are allocated minimum 1207 */ 1208 if (bufspace >= (maxbufspace + nbyteswritten)) { 1209 bp->b_flags |= B_INVAL; 1210 brelse(bp); 1211 goto trytofreespace; 1212 } 1213 1214 /* 1215 * create a map entry for the buffer -- in essence 1216 * reserving the kva space. 1217 */ 1218 if (addr) { 1219 vm_map_insert(buffer_map, NULL, 0, 1220 addr, addr + maxsize, 1221 VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 1222 1223 bp->b_kvabase = (caddr_t) addr; 1224 bp->b_kvasize = maxsize; 1225 } 1226 bp->b_data = bp->b_kvabase; 1227 1228 return (bp); 1229 } 1230 1231 static void 1232 waitfreebuffers(int slpflag, int slptimeo) { 1233 while (numfreebuffers < hifreebuffers) { 1234 flushdirtybuffers(slpflag, slptimeo); 1235 if (numfreebuffers >= hifreebuffers) 1236 break; 1237 needsbuffer |= VFS_BIO_NEED_FREE; 1238 if (tsleep(&needsbuffer, (PRIBIO + 4)|slpflag, "biofre", slptimeo)) 1239 break; 1240 } 1241 } 1242 1243 static void 1244 flushdirtybuffers(int slpflag, int slptimeo) { 1245 int s; 1246 static pid_t flushing = 0; 1247 1248 s = splbio(); 1249 1250 if (flushing) { 1251 if (flushing == curproc->p_pid) { 1252 splx(s); 1253 return; 1254 } 1255 while (flushing) { 1256 if (tsleep(&flushing, (PRIBIO + 4)|slpflag, "biofls", slptimeo)) { 1257 splx(s); 1258 return; 1259 } 1260 } 1261 } 1262 flushing = curproc->p_pid; 1263 1264 while (numdirtybuffers > lodirtybuffers) { 1265 struct buf *bp; 1266 needsbuffer |= VFS_BIO_NEED_LOWLIMIT; 1267 bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); 1268 if (bp == NULL) 1269 bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); 1270 1271 while (bp && ((bp->b_flags & B_DELWRI) == 0)) { 1272 bp = TAILQ_NEXT(bp, b_freelist); 1273 } 1274 1275 if (bp) { 1276 vfs_bio_awrite(bp); 1277 continue; 1278 } 1279 break; 1280 } 1281 1282 flushing = 0; 1283 wakeup(&flushing); 1284 splx(s); 1285 } 1286 1287 /* 1288 * Check to see if a block is currently memory resident. 1289 */ 1290 struct buf * 1291 incore(struct vnode * vp, daddr_t blkno) 1292 { 1293 struct buf *bp; 1294 1295 int s = splbio(); 1296 bp = gbincore(vp, blkno); 1297 splx(s); 1298 return (bp); 1299 } 1300 1301 /* 1302 * Returns true if no I/O is needed to access the 1303 * associated VM object. This is like incore except 1304 * it also hunts around in the VM system for the data. 1305 */ 1306 1307 int 1308 inmem(struct vnode * vp, daddr_t blkno) 1309 { 1310 vm_object_t obj; 1311 vm_offset_t toff, tinc, size; 1312 vm_page_t m; 1313 vm_ooffset_t off; 1314 1315 if (incore(vp, blkno)) 1316 return 1; 1317 if (vp->v_mount == NULL) 1318 return 0; 1319 if ((vp->v_object == NULL) || (vp->v_flag & VOBJBUF) == 0) 1320 return 0; 1321 1322 obj = vp->v_object; 1323 size = PAGE_SIZE; 1324 if (size > vp->v_mount->mnt_stat.f_iosize) 1325 size = vp->v_mount->mnt_stat.f_iosize; 1326 off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize; 1327 1328 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 1329 m = vm_page_lookup(obj, OFF_TO_IDX(off + toff)); 1330 if (!m) 1331 return 0; 1332 tinc = size; 1333 if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK)) 1334 tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK); 1335 if (vm_page_is_valid(m, 1336 (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0) 1337 return 0; 1338 } 1339 return 1; 1340 } 1341 1342 /* 1343 * now we set the dirty range for the buffer -- 1344 * for NFS -- if the file is mapped and pages have 1345 * been written to, let it know. We want the 1346 * entire range of the buffer to be marked dirty if 1347 * any of the pages have been written to for consistancy 1348 * with the b_validoff, b_validend set in the nfs write 1349 * code, and used by the nfs read code. 1350 */ 1351 static void 1352 vfs_setdirty(struct buf *bp) { 1353 int i; 1354 vm_object_t object; 1355 vm_offset_t boffset; 1356 #if 0 1357 vm_offset_t offset; 1358 #endif 1359 1360 /* 1361 * We qualify the scan for modified pages on whether the 1362 * object has been flushed yet. The OBJ_WRITEABLE flag 1363 * is not cleared simply by protecting pages off. 1364 */ 1365 if ((bp->b_flags & B_VMIO) && 1366 ((object = bp->b_pages[0]->object)->flags & (OBJ_WRITEABLE|OBJ_CLEANING))) { 1367 /* 1368 * test the pages to see if they have been modified directly 1369 * by users through the VM system. 1370 */ 1371 for (i = 0; i < bp->b_npages; i++) { 1372 vm_page_flag_clear(bp->b_pages[i], PG_ZERO); 1373 vm_page_test_dirty(bp->b_pages[i]); 1374 } 1375 1376 /* 1377 * scan forwards for the first page modified 1378 */ 1379 for (i = 0; i < bp->b_npages; i++) { 1380 if (bp->b_pages[i]->dirty) { 1381 break; 1382 } 1383 } 1384 boffset = (i << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 1385 if (boffset < bp->b_dirtyoff) { 1386 bp->b_dirtyoff = max(boffset, 0); 1387 } 1388 1389 /* 1390 * scan backwards for the last page modified 1391 */ 1392 for (i = bp->b_npages - 1; i >= 0; --i) { 1393 if (bp->b_pages[i]->dirty) { 1394 break; 1395 } 1396 } 1397 boffset = (i + 1); 1398 #if 0 1399 offset = boffset + bp->b_pages[0]->pindex; 1400 if (offset >= object->size) 1401 boffset = object->size - bp->b_pages[0]->pindex; 1402 #endif 1403 boffset = (boffset << PAGE_SHIFT) - (bp->b_offset & PAGE_MASK); 1404 if (bp->b_dirtyend < boffset) 1405 bp->b_dirtyend = min(boffset, bp->b_bufsize); 1406 } 1407 } 1408 1409 /* 1410 * Get a block given a specified block and offset into a file/device. 1411 */ 1412 struct buf * 1413 getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo) 1414 { 1415 struct buf *bp; 1416 int i, s; 1417 struct bufhashhdr *bh; 1418 1419 #if !defined(MAX_PERF) 1420 if (size > MAXBSIZE) 1421 panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE); 1422 #endif 1423 1424 s = splbio(); 1425 loop: 1426 if (numfreebuffers < lofreebuffers) { 1427 waitfreebuffers(slpflag, slptimeo); 1428 } 1429 1430 if ((bp = gbincore(vp, blkno))) { 1431 if (bp->b_flags & B_BUSY) { 1432 1433 bp->b_flags |= B_WANTED; 1434 if (bp->b_usecount < BUF_MAXUSE) 1435 ++bp->b_usecount; 1436 1437 if (!tsleep(bp, 1438 (PRIBIO + 4) | slpflag, "getblk", slptimeo)) { 1439 goto loop; 1440 } 1441 1442 splx(s); 1443 return (struct buf *) NULL; 1444 } 1445 bp->b_flags |= B_BUSY | B_CACHE; 1446 bremfree(bp); 1447 1448 /* 1449 * check for size inconsistancies (note that they shouldn't 1450 * happen but do when filesystems don't handle the size changes 1451 * correctly.) We are conservative on metadata and don't just 1452 * extend the buffer but write (if needed) and re-constitute it. 1453 */ 1454 1455 if (bp->b_bcount != size) { 1456 if ((bp->b_flags & B_VMIO) && (size <= bp->b_kvasize)) { 1457 allocbuf(bp, size); 1458 } else { 1459 if (bp->b_flags & B_DELWRI) { 1460 bp->b_flags |= B_NOCACHE; 1461 VOP_BWRITE(bp); 1462 } else { 1463 if ((bp->b_flags & B_VMIO) && 1464 (LIST_FIRST(&bp->b_dep) == NULL)) { 1465 bp->b_flags |= B_RELBUF; 1466 brelse(bp); 1467 } else { 1468 bp->b_flags |= B_NOCACHE; 1469 VOP_BWRITE(bp); 1470 } 1471 } 1472 goto loop; 1473 } 1474 } 1475 KASSERT(bp->b_offset != NOOFFSET, 1476 ("getblk: no buffer offset")); 1477 /* 1478 * Check that the constituted buffer really deserves for the 1479 * B_CACHE bit to be set. B_VMIO type buffers might not 1480 * contain fully valid pages. Normal (old-style) buffers 1481 * should be fully valid. 1482 */ 1483 if ( 1484 (bp->b_flags & (B_VMIO|B_CACHE)) == (B_VMIO|B_CACHE) && 1485 (bp->b_vp->v_tag != VT_NFS || bp->b_validend <= 0) 1486 ) { 1487 int checksize = bp->b_bufsize; 1488 int poffset = bp->b_offset & PAGE_MASK; 1489 int resid; 1490 for (i = 0; i < bp->b_npages; i++) { 1491 resid = (checksize > (PAGE_SIZE - poffset)) ? 1492 (PAGE_SIZE - poffset) : checksize; 1493 if (!vm_page_is_valid(bp->b_pages[i], poffset, resid)) { 1494 bp->b_flags &= ~(B_CACHE | B_DONE); 1495 break; 1496 } 1497 checksize -= resid; 1498 poffset = 0; 1499 } 1500 } 1501 1502 if (bp->b_usecount < BUF_MAXUSE) 1503 ++bp->b_usecount; 1504 splx(s); 1505 return (bp); 1506 } else { 1507 int bsize, maxsize, vmio; 1508 off_t offset; 1509 1510 if (vp->v_type == VBLK) 1511 bsize = DEV_BSIZE; 1512 else if (vp->v_mountedhere) 1513 bsize = vp->v_mountedhere->mnt_stat.f_iosize; 1514 else if (vp->v_mount) 1515 bsize = vp->v_mount->mnt_stat.f_iosize; 1516 else 1517 bsize = size; 1518 1519 offset = (off_t)blkno * bsize; 1520 vmio = (vp->v_object != 0) && (vp->v_flag & VOBJBUF); 1521 maxsize = vmio ? size + (offset & PAGE_MASK) : size; 1522 maxsize = imax(maxsize, bsize); 1523 1524 if ((bp = getnewbuf(vp, blkno, 1525 slpflag, slptimeo, size, maxsize)) == 0) { 1526 if (slpflag || slptimeo) { 1527 splx(s); 1528 return NULL; 1529 } 1530 goto loop; 1531 } 1532 1533 /* 1534 * This code is used to make sure that a buffer is not 1535 * created while the getnewbuf routine is blocked. 1536 * This can be a problem whether the vnode is locked or not. 1537 */ 1538 if (gbincore(vp, blkno)) { 1539 bp->b_flags |= B_INVAL; 1540 brelse(bp); 1541 goto loop; 1542 } 1543 1544 /* 1545 * Insert the buffer into the hash, so that it can 1546 * be found by incore. 1547 */ 1548 bp->b_blkno = bp->b_lblkno = blkno; 1549 bp->b_offset = offset; 1550 1551 bgetvp(vp, bp); 1552 LIST_REMOVE(bp, b_hash); 1553 bh = BUFHASH(vp, blkno); 1554 LIST_INSERT_HEAD(bh, bp, b_hash); 1555 1556 if (vmio) { 1557 bp->b_flags |= (B_VMIO | B_CACHE); 1558 #if defined(VFS_BIO_DEBUG) 1559 if (vp->v_type != VREG && vp->v_type != VBLK) 1560 printf("getblk: vmioing file type %d???\n", vp->v_type); 1561 #endif 1562 } else { 1563 bp->b_flags &= ~B_VMIO; 1564 } 1565 1566 allocbuf(bp, size); 1567 1568 splx(s); 1569 return (bp); 1570 } 1571 } 1572 1573 /* 1574 * Get an empty, disassociated buffer of given size. 1575 */ 1576 struct buf * 1577 geteblk(int size) 1578 { 1579 struct buf *bp; 1580 int s; 1581 1582 s = splbio(); 1583 while ((bp = getnewbuf(0, (daddr_t) 0, 0, 0, size, MAXBSIZE)) == 0); 1584 splx(s); 1585 allocbuf(bp, size); 1586 bp->b_flags |= B_INVAL; /* b_dep cleared by getnewbuf() */ 1587 return (bp); 1588 } 1589 1590 1591 /* 1592 * This code constitutes the buffer memory from either anonymous system 1593 * memory (in the case of non-VMIO operations) or from an associated 1594 * VM object (in the case of VMIO operations). 1595 * 1596 * Note that this code is tricky, and has many complications to resolve 1597 * deadlock or inconsistant data situations. Tread lightly!!! 1598 * 1599 * Modify the length of a buffer's underlying buffer storage without 1600 * destroying information (unless, of course the buffer is shrinking). 1601 */ 1602 int 1603 allocbuf(struct buf * bp, int size) 1604 { 1605 1606 int s; 1607 int newbsize, mbsize; 1608 int i; 1609 1610 #if !defined(MAX_PERF) 1611 if (!(bp->b_flags & B_BUSY)) 1612 panic("allocbuf: buffer not busy"); 1613 1614 if (bp->b_kvasize < size) 1615 panic("allocbuf: buffer too small"); 1616 #endif 1617 1618 if ((bp->b_flags & B_VMIO) == 0) { 1619 caddr_t origbuf; 1620 int origbufsize; 1621 /* 1622 * Just get anonymous memory from the kernel 1623 */ 1624 mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 1625 #if !defined(NO_B_MALLOC) 1626 if (bp->b_flags & B_MALLOC) 1627 newbsize = mbsize; 1628 else 1629 #endif 1630 newbsize = round_page(size); 1631 1632 if (newbsize < bp->b_bufsize) { 1633 #if !defined(NO_B_MALLOC) 1634 /* 1635 * malloced buffers are not shrunk 1636 */ 1637 if (bp->b_flags & B_MALLOC) { 1638 if (newbsize) { 1639 bp->b_bcount = size; 1640 } else { 1641 free(bp->b_data, M_BIOBUF); 1642 bufspace -= bp->b_bufsize; 1643 bufmallocspace -= bp->b_bufsize; 1644 bp->b_data = bp->b_kvabase; 1645 bp->b_bufsize = 0; 1646 bp->b_bcount = 0; 1647 bp->b_flags &= ~B_MALLOC; 1648 } 1649 return 1; 1650 } 1651 #endif 1652 vm_hold_free_pages( 1653 bp, 1654 (vm_offset_t) bp->b_data + newbsize, 1655 (vm_offset_t) bp->b_data + bp->b_bufsize); 1656 } else if (newbsize > bp->b_bufsize) { 1657 #if !defined(NO_B_MALLOC) 1658 /* 1659 * We only use malloced memory on the first allocation. 1660 * and revert to page-allocated memory when the buffer grows. 1661 */ 1662 if ( (bufmallocspace < maxbufmallocspace) && 1663 (bp->b_bufsize == 0) && 1664 (mbsize <= PAGE_SIZE/2)) { 1665 1666 bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK); 1667 bp->b_bufsize = mbsize; 1668 bp->b_bcount = size; 1669 bp->b_flags |= B_MALLOC; 1670 bufspace += mbsize; 1671 bufmallocspace += mbsize; 1672 return 1; 1673 } 1674 #endif 1675 origbuf = NULL; 1676 origbufsize = 0; 1677 #if !defined(NO_B_MALLOC) 1678 /* 1679 * If the buffer is growing on its other-than-first allocation, 1680 * then we revert to the page-allocation scheme. 1681 */ 1682 if (bp->b_flags & B_MALLOC) { 1683 origbuf = bp->b_data; 1684 origbufsize = bp->b_bufsize; 1685 bp->b_data = bp->b_kvabase; 1686 bufspace -= bp->b_bufsize; 1687 bufmallocspace -= bp->b_bufsize; 1688 bp->b_bufsize = 0; 1689 bp->b_flags &= ~B_MALLOC; 1690 newbsize = round_page(newbsize); 1691 } 1692 #endif 1693 vm_hold_load_pages( 1694 bp, 1695 (vm_offset_t) bp->b_data + bp->b_bufsize, 1696 (vm_offset_t) bp->b_data + newbsize); 1697 #if !defined(NO_B_MALLOC) 1698 if (origbuf) { 1699 bcopy(origbuf, bp->b_data, origbufsize); 1700 free(origbuf, M_BIOBUF); 1701 } 1702 #endif 1703 } 1704 } else { 1705 vm_page_t m; 1706 int desiredpages; 1707 1708 newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 1709 desiredpages = (size == 0) ? 0 : 1710 num_pages((bp->b_offset & PAGE_MASK) + newbsize); 1711 1712 #if !defined(NO_B_MALLOC) 1713 if (bp->b_flags & B_MALLOC) 1714 panic("allocbuf: VMIO buffer can't be malloced"); 1715 #endif 1716 1717 if (newbsize < bp->b_bufsize) { 1718 if (desiredpages < bp->b_npages) { 1719 for (i = desiredpages; i < bp->b_npages; i++) { 1720 /* 1721 * the page is not freed here -- it 1722 * is the responsibility of 1723 * vnode_pager_setsize. However, we 1724 * have to wait if it is busy in order 1725 * to be able to unwire the page. 1726 */ 1727 m = bp->b_pages[i]; 1728 KASSERT(m != bogus_page, 1729 ("allocbuf: bogus page found")); 1730 1731 while(vm_page_sleep(m, "biodep", &m->busy)) 1732 ; 1733 1734 bp->b_pages[i] = NULL; 1735 vm_page_unwire(m, 0); 1736 } 1737 pmap_qremove((vm_offset_t) trunc_page((vm_offset_t)bp->b_data) + 1738 (desiredpages << PAGE_SHIFT), (bp->b_npages - desiredpages)); 1739 bp->b_npages = desiredpages; 1740 } 1741 } else if (newbsize > bp->b_bufsize) { 1742 vm_object_t obj; 1743 vm_offset_t tinc, toff; 1744 vm_ooffset_t off; 1745 vm_pindex_t objoff; 1746 int pageindex, curbpnpages; 1747 struct vnode *vp; 1748 int bsize; 1749 int orig_validoff = bp->b_validoff; 1750 int orig_validend = bp->b_validend; 1751 1752 vp = bp->b_vp; 1753 1754 if (vp->v_type == VBLK) 1755 bsize = DEV_BSIZE; 1756 else 1757 bsize = vp->v_mount->mnt_stat.f_iosize; 1758 1759 if (bp->b_npages < desiredpages) { 1760 obj = vp->v_object; 1761 tinc = PAGE_SIZE; 1762 1763 off = bp->b_offset; 1764 KASSERT(bp->b_offset != NOOFFSET, 1765 ("allocbuf: no buffer offset")); 1766 curbpnpages = bp->b_npages; 1767 doretry: 1768 bp->b_validoff = orig_validoff; 1769 bp->b_validend = orig_validend; 1770 bp->b_flags |= B_CACHE; 1771 for (toff = 0; toff < newbsize; toff += tinc) { 1772 objoff = OFF_TO_IDX(off + toff); 1773 pageindex = objoff - OFF_TO_IDX(off); 1774 tinc = PAGE_SIZE - ((off + toff) & PAGE_MASK); 1775 if (pageindex < curbpnpages) { 1776 1777 m = bp->b_pages[pageindex]; 1778 #ifdef VFS_BIO_DIAG 1779 if (m->pindex != objoff) 1780 panic("allocbuf: page changed offset?!!!?"); 1781 #endif 1782 if (tinc > (newbsize - toff)) 1783 tinc = newbsize - toff; 1784 if (bp->b_flags & B_CACHE) 1785 vfs_buf_set_valid(bp, off, toff, tinc, m); 1786 continue; 1787 } 1788 m = vm_page_lookup(obj, objoff); 1789 if (!m) { 1790 m = vm_page_alloc(obj, objoff, VM_ALLOC_NORMAL); 1791 if (!m) { 1792 VM_WAIT; 1793 vm_pageout_deficit += (desiredpages - curbpnpages); 1794 goto doretry; 1795 } 1796 1797 vm_page_wire(m); 1798 vm_page_flag_clear(m, PG_BUSY); 1799 bp->b_flags &= ~B_CACHE; 1800 1801 } else if (m->flags & PG_BUSY) { 1802 s = splvm(); 1803 if (m->flags & PG_BUSY) { 1804 vm_page_flag_set(m, PG_WANTED); 1805 tsleep(m, PVM, "pgtblk", 0); 1806 } 1807 splx(s); 1808 goto doretry; 1809 } else { 1810 if ((curproc != pageproc) && 1811 ((m->queue - m->pc) == PQ_CACHE) && 1812 ((cnt.v_free_count + cnt.v_cache_count) < 1813 (cnt.v_free_min + cnt.v_cache_min))) { 1814 pagedaemon_wakeup(); 1815 } 1816 if (tinc > (newbsize - toff)) 1817 tinc = newbsize - toff; 1818 if (bp->b_flags & B_CACHE) 1819 vfs_buf_set_valid(bp, off, toff, tinc, m); 1820 vm_page_flag_clear(m, PG_ZERO); 1821 vm_page_wire(m); 1822 } 1823 bp->b_pages[pageindex] = m; 1824 curbpnpages = pageindex + 1; 1825 } 1826 if (vp->v_tag == VT_NFS && 1827 vp->v_type != VBLK) { 1828 if (bp->b_dirtyend > 0) { 1829 bp->b_validoff = min(bp->b_validoff, bp->b_dirtyoff); 1830 bp->b_validend = max(bp->b_validend, bp->b_dirtyend); 1831 } 1832 if (bp->b_validend == 0) 1833 bp->b_flags &= ~B_CACHE; 1834 } 1835 bp->b_data = (caddr_t) trunc_page((vm_offset_t)bp->b_data); 1836 bp->b_npages = curbpnpages; 1837 pmap_qenter((vm_offset_t) bp->b_data, 1838 bp->b_pages, bp->b_npages); 1839 ((vm_offset_t) bp->b_data) |= off & PAGE_MASK; 1840 } 1841 } 1842 } 1843 if (bp->b_flags & B_VMIO) 1844 vmiospace += (newbsize - bp->b_bufsize); 1845 bufspace += (newbsize - bp->b_bufsize); 1846 bp->b_bufsize = newbsize; 1847 bp->b_bcount = size; 1848 return 1; 1849 } 1850 1851 /* 1852 * Wait for buffer I/O completion, returning error status. 1853 */ 1854 int 1855 biowait(register struct buf * bp) 1856 { 1857 int s; 1858 1859 s = splbio(); 1860 while ((bp->b_flags & B_DONE) == 0) 1861 #if defined(NO_SCHEDULE_MODS) 1862 tsleep(bp, PRIBIO, "biowait", 0); 1863 #else 1864 if (bp->b_flags & B_READ) 1865 tsleep(bp, PRIBIO, "biord", 0); 1866 else 1867 tsleep(bp, PRIBIO, "biowr", 0); 1868 #endif 1869 splx(s); 1870 if (bp->b_flags & B_EINTR) { 1871 bp->b_flags &= ~B_EINTR; 1872 return (EINTR); 1873 } 1874 if (bp->b_flags & B_ERROR) { 1875 return (bp->b_error ? bp->b_error : EIO); 1876 } else { 1877 return (0); 1878 } 1879 } 1880 1881 /* 1882 * Finish I/O on a buffer, calling an optional function. 1883 * This is usually called from interrupt level, so process blocking 1884 * is not *a good idea*. 1885 */ 1886 void 1887 biodone(register struct buf * bp) 1888 { 1889 int s; 1890 1891 s = splbio(); 1892 1893 #if !defined(MAX_PERF) 1894 if (!(bp->b_flags & B_BUSY)) 1895 panic("biodone: buffer not busy"); 1896 #endif 1897 1898 if (bp->b_flags & B_DONE) { 1899 splx(s); 1900 #if !defined(MAX_PERF) 1901 printf("biodone: buffer already done\n"); 1902 #endif 1903 return; 1904 } 1905 bp->b_flags |= B_DONE; 1906 1907 if (bp->b_flags & B_FREEBUF) { 1908 brelse(bp); 1909 splx(s); 1910 return; 1911 } 1912 1913 if ((bp->b_flags & B_READ) == 0) { 1914 vwakeup(bp); 1915 } 1916 1917 /* call optional completion function if requested */ 1918 if (bp->b_flags & B_CALL) { 1919 bp->b_flags &= ~B_CALL; 1920 (*bp->b_iodone) (bp); 1921 splx(s); 1922 return; 1923 } 1924 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete) 1925 (*bioops.io_complete)(bp); 1926 1927 if (bp->b_flags & B_VMIO) { 1928 int i, resid; 1929 vm_ooffset_t foff; 1930 vm_page_t m; 1931 vm_object_t obj; 1932 int iosize; 1933 struct vnode *vp = bp->b_vp; 1934 1935 obj = vp->v_object; 1936 1937 #if defined(VFS_BIO_DEBUG) 1938 if (vp->v_usecount == 0) { 1939 panic("biodone: zero vnode ref count"); 1940 } 1941 1942 if (vp->v_object == NULL) { 1943 panic("biodone: missing VM object"); 1944 } 1945 1946 if ((vp->v_flag & VOBJBUF) == 0) { 1947 panic("biodone: vnode is not setup for merged cache"); 1948 } 1949 #endif 1950 1951 foff = bp->b_offset; 1952 KASSERT(bp->b_offset != NOOFFSET, 1953 ("biodone: no buffer offset")); 1954 1955 #if !defined(MAX_PERF) 1956 if (!obj) { 1957 panic("biodone: no object"); 1958 } 1959 #endif 1960 #if defined(VFS_BIO_DEBUG) 1961 if (obj->paging_in_progress < bp->b_npages) { 1962 printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n", 1963 obj->paging_in_progress, bp->b_npages); 1964 } 1965 #endif 1966 iosize = bp->b_bufsize; 1967 for (i = 0; i < bp->b_npages; i++) { 1968 int bogusflag = 0; 1969 m = bp->b_pages[i]; 1970 if (m == bogus_page) { 1971 bogusflag = 1; 1972 m = vm_page_lookup(obj, OFF_TO_IDX(foff)); 1973 if (!m) { 1974 #if defined(VFS_BIO_DEBUG) 1975 printf("biodone: page disappeared\n"); 1976 #endif 1977 vm_object_pip_subtract(obj, 1); 1978 continue; 1979 } 1980 bp->b_pages[i] = m; 1981 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), bp->b_pages, bp->b_npages); 1982 } 1983 #if defined(VFS_BIO_DEBUG) 1984 if (OFF_TO_IDX(foff) != m->pindex) { 1985 printf( 1986 "biodone: foff(%lu)/m->pindex(%d) mismatch\n", 1987 (unsigned long)foff, m->pindex); 1988 } 1989 #endif 1990 resid = IDX_TO_OFF(m->pindex + 1) - foff; 1991 if (resid > iosize) 1992 resid = iosize; 1993 1994 /* 1995 * In the write case, the valid and clean bits are 1996 * already changed correctly, so we only need to do this 1997 * here in the read case. 1998 */ 1999 if ((bp->b_flags & B_READ) && !bogusflag && resid > 0) { 2000 vfs_page_set_valid(bp, foff, i, m); 2001 } 2002 vm_page_flag_clear(m, PG_ZERO); 2003 2004 /* 2005 * when debugging new filesystems or buffer I/O methods, this 2006 * is the most common error that pops up. if you see this, you 2007 * have not set the page busy flag correctly!!! 2008 */ 2009 if (m->busy == 0) { 2010 #if !defined(MAX_PERF) 2011 printf("biodone: page busy < 0, " 2012 "pindex: %d, foff: 0x(%x,%x), " 2013 "resid: %d, index: %d\n", 2014 (int) m->pindex, (int)(foff >> 32), 2015 (int) foff & 0xffffffff, resid, i); 2016 #endif 2017 if (vp->v_type != VBLK) 2018 #if !defined(MAX_PERF) 2019 printf(" iosize: %ld, lblkno: %d, flags: 0x%lx, npages: %d\n", 2020 bp->b_vp->v_mount->mnt_stat.f_iosize, 2021 (int) bp->b_lblkno, 2022 bp->b_flags, bp->b_npages); 2023 else 2024 printf(" VDEV, lblkno: %d, flags: 0x%lx, npages: %d\n", 2025 (int) bp->b_lblkno, 2026 bp->b_flags, bp->b_npages); 2027 printf(" valid: 0x%x, dirty: 0x%x, wired: %d\n", 2028 m->valid, m->dirty, m->wire_count); 2029 #endif 2030 panic("biodone: page busy < 0\n"); 2031 } 2032 vm_page_io_finish(m); 2033 vm_object_pip_subtract(obj, 1); 2034 foff += resid; 2035 iosize -= resid; 2036 } 2037 if (obj && 2038 (obj->paging_in_progress == 0) && 2039 (obj->flags & OBJ_PIPWNT)) { 2040 vm_object_clear_flag(obj, OBJ_PIPWNT); 2041 wakeup(obj); 2042 } 2043 } 2044 /* 2045 * For asynchronous completions, release the buffer now. The brelse 2046 * checks for B_WANTED and will do the wakeup there if necessary - so 2047 * no need to do a wakeup here in the async case. 2048 */ 2049 2050 if (bp->b_flags & B_ASYNC) { 2051 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0) 2052 brelse(bp); 2053 else 2054 bqrelse(bp); 2055 } else { 2056 bp->b_flags &= ~B_WANTED; 2057 wakeup(bp); 2058 } 2059 splx(s); 2060 } 2061 2062 #if 0 /* not with kirks code */ 2063 static int vfs_update_interval = 30; 2064 2065 static void 2066 vfs_update() 2067 { 2068 while (1) { 2069 tsleep(&vfs_update_wakeup, PUSER, "update", 2070 hz * vfs_update_interval); 2071 vfs_update_wakeup = 0; 2072 sync(curproc, NULL); 2073 } 2074 } 2075 2076 static int 2077 sysctl_kern_updateinterval SYSCTL_HANDLER_ARGS 2078 { 2079 int error = sysctl_handle_int(oidp, 2080 oidp->oid_arg1, oidp->oid_arg2, req); 2081 if (!error) 2082 wakeup(&vfs_update_wakeup); 2083 return error; 2084 } 2085 2086 SYSCTL_PROC(_kern, KERN_UPDATEINTERVAL, update, CTLTYPE_INT|CTLFLAG_RW, 2087 &vfs_update_interval, 0, sysctl_kern_updateinterval, "I", ""); 2088 2089 #endif 2090 2091 2092 /* 2093 * This routine is called in lieu of iodone in the case of 2094 * incomplete I/O. This keeps the busy status for pages 2095 * consistant. 2096 */ 2097 void 2098 vfs_unbusy_pages(struct buf * bp) 2099 { 2100 int i; 2101 2102 if (bp->b_flags & B_VMIO) { 2103 struct vnode *vp = bp->b_vp; 2104 vm_object_t obj = vp->v_object; 2105 2106 for (i = 0; i < bp->b_npages; i++) { 2107 vm_page_t m = bp->b_pages[i]; 2108 2109 if (m == bogus_page) { 2110 m = vm_page_lookup(obj, OFF_TO_IDX(bp->b_offset) + i); 2111 #if !defined(MAX_PERF) 2112 if (!m) { 2113 panic("vfs_unbusy_pages: page missing\n"); 2114 } 2115 #endif 2116 bp->b_pages[i] = m; 2117 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), bp->b_pages, bp->b_npages); 2118 } 2119 vm_object_pip_subtract(obj, 1); 2120 vm_page_flag_clear(m, PG_ZERO); 2121 vm_page_io_finish(m); 2122 } 2123 if (obj->paging_in_progress == 0 && 2124 (obj->flags & OBJ_PIPWNT)) { 2125 vm_object_clear_flag(obj, OBJ_PIPWNT); 2126 wakeup(obj); 2127 } 2128 } 2129 } 2130 2131 /* 2132 * Set NFS' b_validoff and b_validend fields from the valid bits 2133 * of a page. If the consumer is not NFS, and the page is not 2134 * valid for the entire range, clear the B_CACHE flag to force 2135 * the consumer to re-read the page. 2136 */ 2137 static void 2138 vfs_buf_set_valid(struct buf *bp, 2139 vm_ooffset_t foff, vm_offset_t off, vm_offset_t size, 2140 vm_page_t m) 2141 { 2142 if (bp->b_vp->v_tag == VT_NFS && bp->b_vp->v_type != VBLK) { 2143 vm_offset_t svalid, evalid; 2144 int validbits = m->valid >> (((foff+off)&PAGE_MASK)/DEV_BSIZE); 2145 2146 /* 2147 * This only bothers with the first valid range in the 2148 * page. 2149 */ 2150 svalid = off; 2151 while (validbits && !(validbits & 1)) { 2152 svalid += DEV_BSIZE; 2153 validbits >>= 1; 2154 } 2155 evalid = svalid; 2156 while (validbits & 1) { 2157 evalid += DEV_BSIZE; 2158 validbits >>= 1; 2159 } 2160 evalid = min(evalid, off + size); 2161 /* 2162 * Make sure this range is contiguous with the range 2163 * built up from previous pages. If not, then we will 2164 * just use the range from the previous pages. 2165 */ 2166 if (svalid == bp->b_validend) { 2167 bp->b_validoff = min(bp->b_validoff, svalid); 2168 bp->b_validend = max(bp->b_validend, evalid); 2169 } 2170 } else if (!vm_page_is_valid(m, 2171 (vm_offset_t) ((foff + off) & PAGE_MASK), 2172 size)) { 2173 bp->b_flags &= ~B_CACHE; 2174 } 2175 } 2176 2177 /* 2178 * Set the valid bits in a page, taking care of the b_validoff, 2179 * b_validend fields which NFS uses to optimise small reads. Off is 2180 * the offset within the file and pageno is the page index within the buf. 2181 */ 2182 static void 2183 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, int pageno, vm_page_t m) 2184 { 2185 struct vnode *vp = bp->b_vp; 2186 vm_ooffset_t soff, eoff; 2187 2188 soff = off; 2189 eoff = (off + PAGE_SIZE) & ~PAGE_MASK; 2190 if (eoff > bp->b_offset + bp->b_bufsize) 2191 eoff = bp->b_offset + bp->b_bufsize; 2192 if (vp->v_tag == VT_NFS && vp->v_type != VBLK) { 2193 vm_ooffset_t sv, ev; 2194 vm_page_set_invalid(m, 2195 (vm_offset_t) (soff & PAGE_MASK), 2196 (vm_offset_t) (eoff - soff)); 2197 sv = (bp->b_offset + bp->b_validoff + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 2198 ev = (bp->b_offset + bp->b_validend + (DEV_BSIZE - 1)) & 2199 ~(DEV_BSIZE - 1); 2200 soff = qmax(sv, soff); 2201 eoff = qmin(ev, eoff); 2202 } 2203 if (eoff > soff) 2204 vm_page_set_validclean(m, 2205 (vm_offset_t) (soff & PAGE_MASK), 2206 (vm_offset_t) (eoff - soff)); 2207 } 2208 2209 /* 2210 * This routine is called before a device strategy routine. 2211 * It is used to tell the VM system that paging I/O is in 2212 * progress, and treat the pages associated with the buffer 2213 * almost as being PG_BUSY. Also the object paging_in_progress 2214 * flag is handled to make sure that the object doesn't become 2215 * inconsistant. 2216 */ 2217 void 2218 vfs_busy_pages(struct buf * bp, int clear_modify) 2219 { 2220 int i, bogus; 2221 2222 if (bp->b_flags & B_VMIO) { 2223 struct vnode *vp = bp->b_vp; 2224 vm_object_t obj = vp->v_object; 2225 vm_ooffset_t foff; 2226 2227 foff = bp->b_offset; 2228 KASSERT(bp->b_offset != NOOFFSET, 2229 ("vfs_busy_pages: no buffer offset")); 2230 vfs_setdirty(bp); 2231 2232 retry: 2233 for (i = 0; i < bp->b_npages; i++) { 2234 vm_page_t m = bp->b_pages[i]; 2235 if (vm_page_sleep(m, "vbpage", NULL)) 2236 goto retry; 2237 } 2238 2239 bogus = 0; 2240 for (i = 0; i < bp->b_npages; i++) { 2241 vm_page_t m = bp->b_pages[i]; 2242 2243 vm_page_flag_clear(m, PG_ZERO); 2244 if ((bp->b_flags & B_CLUSTER) == 0) { 2245 vm_object_pip_add(obj, 1); 2246 vm_page_io_start(m); 2247 } 2248 2249 vm_page_protect(m, VM_PROT_NONE); 2250 if (clear_modify) 2251 vfs_page_set_valid(bp, foff, i, m); 2252 else if (m->valid == VM_PAGE_BITS_ALL && 2253 (bp->b_flags & B_CACHE) == 0) { 2254 bp->b_pages[i] = bogus_page; 2255 bogus++; 2256 } 2257 foff = (foff + PAGE_SIZE) & ~PAGE_MASK; 2258 } 2259 if (bogus) 2260 pmap_qenter(trunc_page((vm_offset_t)bp->b_data), bp->b_pages, bp->b_npages); 2261 } 2262 } 2263 2264 /* 2265 * Tell the VM system that the pages associated with this buffer 2266 * are clean. This is used for delayed writes where the data is 2267 * going to go to disk eventually without additional VM intevention. 2268 */ 2269 void 2270 vfs_clean_pages(struct buf * bp) 2271 { 2272 int i; 2273 2274 if (bp->b_flags & B_VMIO) { 2275 vm_ooffset_t foff; 2276 foff = bp->b_offset; 2277 KASSERT(bp->b_offset != NOOFFSET, 2278 ("vfs_clean_pages: no buffer offset")); 2279 for (i = 0; i < bp->b_npages; i++) { 2280 vm_page_t m = bp->b_pages[i]; 2281 vfs_page_set_valid(bp, foff, i, m); 2282 foff = (foff + PAGE_SIZE) & ~PAGE_MASK; 2283 } 2284 } 2285 } 2286 2287 void 2288 vfs_bio_clrbuf(struct buf *bp) { 2289 int i, mask = 0; 2290 caddr_t sa, ea; 2291 if ((bp->b_flags & (B_VMIO | B_MALLOC)) == B_VMIO) { 2292 if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE) && 2293 (bp->b_offset & PAGE_MASK) == 0) { 2294 mask = (1 << (bp->b_bufsize / DEV_BSIZE)) - 1; 2295 if (((bp->b_pages[0]->flags & PG_ZERO) == 0) && 2296 ((bp->b_pages[0]->valid & mask) != mask)) { 2297 bzero(bp->b_data, bp->b_bufsize); 2298 } 2299 bp->b_pages[0]->valid |= mask; 2300 bp->b_resid = 0; 2301 return; 2302 } 2303 ea = sa = bp->b_data; 2304 for(i=0;i<bp->b_npages;i++,sa=ea) { 2305 int j = ((u_long)sa & PAGE_MASK) / DEV_BSIZE; 2306 ea = (caddr_t)trunc_page((vm_offset_t)sa + PAGE_SIZE); 2307 ea = (caddr_t)ulmin((u_long)ea, 2308 (u_long)bp->b_data + bp->b_bufsize); 2309 mask = ((1 << ((ea - sa) / DEV_BSIZE)) - 1) << j; 2310 if ((bp->b_pages[i]->valid & mask) == mask) 2311 continue; 2312 if ((bp->b_pages[i]->valid & mask) == 0) { 2313 if ((bp->b_pages[i]->flags & PG_ZERO) == 0) { 2314 bzero(sa, ea - sa); 2315 } 2316 } else { 2317 for (; sa < ea; sa += DEV_BSIZE, j++) { 2318 if (((bp->b_pages[i]->flags & PG_ZERO) == 0) && 2319 (bp->b_pages[i]->valid & (1<<j)) == 0) 2320 bzero(sa, DEV_BSIZE); 2321 } 2322 } 2323 bp->b_pages[i]->valid |= mask; 2324 vm_page_flag_clear(bp->b_pages[i], PG_ZERO); 2325 } 2326 bp->b_resid = 0; 2327 } else { 2328 clrbuf(bp); 2329 } 2330 } 2331 2332 /* 2333 * vm_hold_load_pages and vm_hold_unload pages get pages into 2334 * a buffers address space. The pages are anonymous and are 2335 * not associated with a file object. 2336 */ 2337 void 2338 vm_hold_load_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) 2339 { 2340 vm_offset_t pg; 2341 vm_page_t p; 2342 int index; 2343 2344 to = round_page(to); 2345 from = round_page(from); 2346 index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 2347 2348 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 2349 2350 tryagain: 2351 2352 p = vm_page_alloc(kernel_object, 2353 ((pg - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), 2354 VM_ALLOC_NORMAL); 2355 if (!p) { 2356 vm_pageout_deficit += (to - from) >> PAGE_SHIFT; 2357 VM_WAIT; 2358 goto tryagain; 2359 } 2360 vm_page_wire(p); 2361 p->valid = VM_PAGE_BITS_ALL; 2362 vm_page_flag_clear(p, PG_ZERO); 2363 pmap_kenter(pg, VM_PAGE_TO_PHYS(p)); 2364 bp->b_pages[index] = p; 2365 vm_page_wakeup(p); 2366 } 2367 bp->b_npages = index; 2368 } 2369 2370 void 2371 vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) 2372 { 2373 vm_offset_t pg; 2374 vm_page_t p; 2375 int index, newnpages; 2376 2377 from = round_page(from); 2378 to = round_page(to); 2379 newnpages = index = (from - trunc_page((vm_offset_t)bp->b_data)) >> PAGE_SHIFT; 2380 2381 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 2382 p = bp->b_pages[index]; 2383 if (p && (index < bp->b_npages)) { 2384 #if !defined(MAX_PERF) 2385 if (p->busy) { 2386 printf("vm_hold_free_pages: blkno: %d, lblkno: %d\n", 2387 bp->b_blkno, bp->b_lblkno); 2388 } 2389 #endif 2390 bp->b_pages[index] = NULL; 2391 pmap_kremove(pg); 2392 vm_page_busy(p); 2393 vm_page_unwire(p, 0); 2394 vm_page_free(p); 2395 } 2396 } 2397 bp->b_npages = newnpages; 2398 } 2399 2400 2401 #include "opt_ddb.h" 2402 #ifdef DDB 2403 #include <ddb/ddb.h> 2404 2405 DB_SHOW_COMMAND(buffer, db_show_buffer) 2406 { 2407 /* get args */ 2408 struct buf *bp = (struct buf *)addr; 2409 2410 if (!have_addr) { 2411 db_printf("usage: show buffer <addr>\n"); 2412 return; 2413 } 2414 2415 db_printf("b_proc = %p,\nb_flags = 0x%b\n", (void *)bp->b_proc, 2416 (u_int)bp->b_flags, PRINT_BUF_FLAGS); 2417 db_printf("b_error = %d, b_bufsize = %ld, b_bcount = %ld, " 2418 "b_resid = %ld\nb_dev = 0x%x, b_data = %p, " 2419 "b_blkno = %d, b_pblkno = %d\n", 2420 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 2421 bp->b_dev, bp->b_data, bp->b_blkno, bp->b_pblkno); 2422 if (bp->b_npages) { 2423 int i; 2424 db_printf("b_npages = %d, pages(OBJ, IDX, PA): ", bp->b_npages); 2425 for (i = 0; i < bp->b_npages; i++) { 2426 vm_page_t m; 2427 m = bp->b_pages[i]; 2428 db_printf("(%p, 0x%lx, 0x%lx)", (void *)m->object, 2429 (u_long)m->pindex, (u_long)VM_PAGE_TO_PHYS(m)); 2430 if ((i + 1) < bp->b_npages) 2431 db_printf(","); 2432 } 2433 db_printf("\n"); 2434 } 2435 } 2436 #endif /* DDB */
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